General Information

What are beetles?

Beetles belong to the order Coleoptera, the most species-rich order of any living organism, with over 400,000 described species. They are found on every continent except Antarctica, and their defining feature is the hardened forewings (elytra) that protect the delicate flight wings beneath.

In the hobby, three groups are particularly popular:

• Flower beetles (Cetoniinae). Colourful, active, and generally the easiest to keep. Many species are iridescent and diurnal.
• Rhinoceros beetles (Dynastinae). Famous for their horns. Males of large species like Dynastes and Megasoma are some of the largest insects you can keep.
• Stag beetles (Lucanidae). Known for their enlarged mandibles, which males use in combat. Many species are prized for their dramatic appearance.

Complete metamorphosis

All beetles undergo complete metamorphosis: egg → larva (grub) → pupa → adult. This applies across every beetle group. Understanding each stage helps you give them what they need. Larvae and adults have completely different requirements, so many keepers maintain separate containers for each.

Larval periods vary hugely by species. Small flower beetles like Pachnoda may complete their larval stage in as little as 3 months, while large Dynastinae species can spend 2 years or more as larvae before pupating.

Why beetle keeping is rewarding

It never gets old watching a fat white grub turn into an armoured, iridescent adult. Some species are dead simple and breed easily in a small tub. Others take years as larvae and leave less room for mistakes.

Common UK hobby species

• Pachnoda marginata (sun beetle). A flower beetle and the classic beginner species. Quick life cycle, hardy, and breeds prolifically.
• Trypoxylus dichotomus (Japanese rhinoceros beetle). A beginner-to-intermediate rhino beetle with large horns and a manageable larval period of around 12 months.
• Xylotrupes gideon (Siamese rhinoceros beetle). Widely available from European breeders, legal in the UK, good beginner-intermediate Dynastinae
• Mecynorrhina torquata (giant African flower beetle). An intermediate flower beetle that produces some of the largest Cetoniinae adults, with good colour variation.

General care basics

While each species has its own requirements, the following principles apply broadly across beetle groups:

• Larval substrate: Most beetle larvae feed on well-rotted deciduous wood (oak, beech, or fruit wood) mixed with coco coir or leaf litter. Dynastinae and Lucanidae larvae do well on flake soil. Keep substrate moist but never waterlogged, and provide a depth of at least 15 cm.
• Pupation: Larvae will stop feeding and become sluggish when ready to pupate. Do not disturb the substrate during this time. Pupae are extremely fragile.
• Adult feeding: Many adult flower beetles and rhinoceros beetles feed on fruit (banana, mango, apple, melon) and beetle jelly, while stag beetles primarily feed on tree sap. Some adult beetles barely feed at all, living off reserves from the larval stage. Replace fresh food every 1–2 days to prevent mould.
• Temperature: Most hobby species do well at 20–26°C. Tropical species may prefer the warmer end of this range.
• Humidity: 60–80% is suitable for most species. Mist the enclosure lightly if it dries out.
• Ventilation: Good airflow prevents mould and stagnant conditions. Use a well-ventilated enclosure with a secure lid.

Breeding

To breed, provide adults with a deep substrate of rotted wood or flake soil. Females will burrow down to lay eggs. Larvae will hatch within 2–4 weeks and begin feeding on the substrate around them. Keep the breeding enclosure warm (24–26°C) and consistently moist to encourage egg-laying and larval development.